The invention relates to orthopedic-fixation devices and in particular to a clamping coupling for a fixator of the nature disclosed in U.S. Pat. No. 4,312,336 (now Reissue Pat. No. Re. 31,809).
Said patent disclosed an external fixator having a central body part with clamping means at each of the respective ends of the body part. Each of the clamping means is developed (1) to receive and fix in place bone screws or pins and (2) to detachably achieve a ball-joint connection to the central body part, via a bayonet lock or via a threaded lock. In this way, the bone screws are connected to the central body part of the fixator.
More specifically, with respect to the clamping means for an external fixator, clamping action is achieved by and between elongate confronting faces of two half shells, the confronting faces having corresponding transverse grooves by which one or more bone screws, pins or the like are located when the half shells are bolted to each other to secure their clamped assembly to the bone screws or the like. The longitudinal end of one of these half shells carries ball-joint connecting means that is adapted for detachable connection to a coacting ball-joint connection at either of the two longitudinal ends of an external fixator.
Although bone-screw clamps of the character indicated have been generally adopted and are satisfactory, they do involve totally separable component parts and in certain cases exhibit manipulating inconvenience in the course of assembly to and/or disassembly from bone screws.